Recently, the disk apparatus is in a trend of small and thin design, and the mechanism for ejecting and accommodating a tray for mounting a disk thereon is limited in reduction of its thickness in the mechanism of rack and pinion using a motor.
In the eject mechanism for ejecting the tray, generally, the user pushes the button to eject. The eject operation is effected in two manners. In one operation, by the force of pushing the button by the user, the tray is directly unlocked, and the tray is ejected, which is a mechanical eject type, and in other operation, pushing of the button is electrically detected, and the tray is unlocked electrically by the command from the controller, which is a soft eject type. In the soft eject type, the tray can be ejected by a software command according to the guide displayed on a screen of a personal computer or the like.
A conventional disk apparatus is described below. FIG. 9 is an internal structural diagram of a conventional disk apparatus. In FIG. 9, reference numeral 1 is a main body chassis, 2 is an optical pickup, 3 is a tray, 4 is a rail, 7 is an eject button, 8 is a detection switch, 9 is a controller, 10 is a lock arm, 11 is a lock arm shaft, and 12 is a solenoid.
The lock arm 10, lock arm shaft 11 and solenoid 12 compose a tray lock mechanism. The main body chassis 1 supports this entire disk apparatus.
The tray 3 is for mounting a disk (not shown) on, and also accommodates the optical pickup 2, controller 9, eject button 7, detection switch 8 and others as described below. The tray 3 is also provided with a stopper pin 13.
The rail 4 holds the tray 3 in the main body chassis 1, and confines the tray 3 in its operating direction. The lock arm 10 has a pawl at its end, and locks the tray 3 at its stopper pin 13. The eject button 7 transmits an eject command operation of the tray 3 to the detection switch 8. The controller 9 receives the detection of eject operation from the detection switch 8, and applies a voltage to the solenoid 12. The solenoid 12 receives the voltage from the controller 9, and unlocks the lock arm 10.
The disk eject operation for loading or unloading a disk in thus constituted disk apparatus is described below. First, the tray 3 is in locked state. Herein, when the user pushes the eject button 7 provided in the tray 3, this operation is detected by the detection switch 8, and a command for starting tray eject operation is sent to the controller 9. Receiving the command, the controller 9 immediately applies a voltage to the solenoid 12. When the solenoid 12 is put in action, one end of the lock arm 10 is attracted, and the lock arm 10 is rotated, and the pawl at the other end of the lock arm 10 is dislocated from the stopper pin 13, thereby unlocking the tray 13.
At this time, when the user draws out the tray 3, it is ready to load or unload the disk. When accommodating the disk, the user pushes in the tray 3, then the pawl of the lock arm 10 is hooked on the stopper pin 13 of the tray so as to be in a state for accommodation.
However, in the soft eject mechanism using the solenoid as a in this disk apparatus, the greatest barrier for reducing the thickness was the thickness of the solenoid. The solenoid is formed by winding a coil around a moving iron core, and further surrounding the periphery with a metal plate, and basically the section is nearly a square structurally, and it is very hard to reduce the thickness. Moreover, as often seen in recent thin type disk apparatuses, the space for the solenoid must be provided by cutting off part of the main body chassis by saving the space of the printed circuit board for controlling the entire disk apparatus, which is contrary to the demand for small and thin design of disk apparatus.
At the time of locking, a static frictional force by the thrusting force when ejecting the tray is applied to the tray and the lock arm for locking the tray. Therefore, to unlock the tray, in order to overcome this static frictional force, it is preferred to use an actuator which is capable of obtaining a large force when starting to move the lock arm. However, since the conventional solenoid is designed to attract the iron core to the yoke plate by the magnetic force by magnetizing the yoke plate by the coil, the characteristic of the attracting force of the solenoid is not uniform in the moving stroke of the iron core, and force is not produced unless the iron core comes closer to the yoke plate. That is, in the initial state where the iron core is remote, the force is weak, and the force is gradually intensified as the iron core is attracted closer. Such starting characteristic of the solenoid is reverse to the required characteristic when unlocking, and hence the solenoid is not suited to the actuator used in unlocking. Moreover, if the iron core is too remote, the magnetic force of the yoke plate does not reach, and the stroke of the actuator was very short for use in unlocking.
It is hence an object of the invention to present a disk apparatus capable of reducing the thickness of the lock mechanism and electric unlocking mechanism of the tray and others for mounting a disk on, and also reducing the size of the entire apparatus.